How can you NOT go with this? Although of course it would be LF, CF, RF.
That was my first thought, too. 
Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India?
intern —> temp —> customer service rep —> account executive —> Sr. account executive —> executive vice president —> CEO —> Chairman of the board —> Bangkok 10 year old prostitute
I like that, leaves room for expansion.
Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner, Blitzen, Rudolph
When I did database management I used old fashioned women’s names to differentiate. When my coworkers (and manager) found out they thought it was hilarious and adopted it as procedure. We named them in alphabetical order to know what was older. So:
Abigail, Beatrice, Clara, Dolores, Eleanor, Frances, Gladys, Harriet, Imogen
When I left to have my kid the only active ones were Gladys and Harriet with Imogen about to launch.
Bashful, Doc, Dopey, Grumpy, Happy, Sleepy, Sneezy, Snow, and Charming.
(unabashedly stolen, with modifications, from my high school word processing classroom)
Clusters, macroclusters, microclusters, pods, micropods, minipods, macropods, macronuggets, supernuggets, bulbo-aggregates, and pings.
Some should tie into other clusters, pods, nuggets, bulbo-aggregates, and pings, and some should remain essentially stable.
colloid, clay, silt, fine sand, course sand, granule, pebble, cobble, boulder
I’m a big fan of 1, 2, 3, 4, 5, 6, 7, 8, 9, myself. I hate dealing with things that assume that I’m going to make the same assumptions as the creators did when they created it (I’m looking at you, Machine Element Design textbook!)
If you don’t want to just number them, then name them for whatever will be in the levels.
Finance Department Standard Operating Procedures < Main Office Standard Operating Procedures < USA Documentation and Practices < North America Documentation and Practices < … ok, I’m not making it to 9 with those examples, but I think it’s clear where I’m going, no? That way if someone wants to know what the SOP is about bringing guests to the office building in Wisconsin, they don’t have to think “would that be under Theodore or Chtulu?”
Assume that one day, someone else is going to have to take over from you, perhaps after a fire that burned your explanatory post-it note collection, and if it doesn’t make sense immediately, then change what you’re doing. If you’re the only one that “gets it”, then there’s a problem.
Jehovah, Jesus, Mary, Joseph, Peter, Barabas, Pilate, Satan, Glen Beck
An easy one would be a military hierarchy:
President
General
Colonel
Major
Captain
Lieutenant
Sergeant
Corporal
Private
I know who Jon’n. Chance was; no idea if Jonathan is your real name or not, but you should put your own brand on it by taking a 9 letter version of your own name. Example: if your name really is Jonathan do “I, Jonathan”.
Ion
Jolt
Ozone
Nitro
Atomic
Torpedo
Hydrogen
Armor Piercing
Nuclear
etchings->papyrus->parchment->paper->scroll->codex->print->internet->ESP
mnemosyne has the right idea. Figure out what criteria is being used to organize these documents at each level, then name the level after the most prominent/important one. If the industry has a standard method of organizing information in its regulations or standards, adapt it. That way it’s familiar to everyone using it and you’re not spending time reinventing the wheel.
Don’t go down nine levels. That is flat flamin’ ridiculous.
Apollo, Bacchus, Chronos, Doofus (the god of computers). That’s all you need.
Gandalf, Aragorn, Legolas, Gimli, Boromir, Frodo, Sam, Pippin, Merry
Nine levels? What sort of CMS are you working on? I go for:
Category
Sub-Category
Sub-Sub-Category…
Document